Heat stress decreased transpiration but increased evapotranspiration in gerbera

Zaiqiang Yang; Yuhan Jiang; Rangjian Qiu; Xuewen Gong; Evgenios Agathokleous; Wei Hu; Brent Clothier

doi:10.3389/fpls.2023.1119076

Heat stress decreased transpiration but increased evapotranspiration in gerbera

Front Plant Sci. 2023 Jan 19:14:1119076. doi: 10.3389/fpls.2023.1119076. eCollection 2023.

Authors

Zaiqiang Yang¹, Yuhan Jiang¹, Rangjian Qiu², Xuewen Gong³, Evgenios Agathokleous¹, Wei Hu⁴, Brent Clothier⁵

Affiliations

¹ Jiangsu Key Laboratory of Agricultural Meteorology, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China.
² State Key Laboratory of Water Resources and Hydropower Engineering Science, School of Water Resources and Hyperpower Engineering, Wuhan University, Wuhan, China.
³ School of Water Conservancy, North China University of Water Resources and Electric Power, Henan Key Laboratory of Crop Water Use, Zhengzhou, China.
⁴ The New Zealand Institute for Plant and Food Research Ltd, Christchurch, New Zealand.
⁵ The New Zealand Institute for Plant and Food Research Ltd, Auckland, New Zealand.

Abstract

Heat stress is a major constraint for plant production, and evapotranspiration is highly linked to plant production. However, the response mechanism of evapotranspiration to heat stress remains unclear. Here, we investigated the effects of heat stress during two main growth stages on transpiration and evapotranspiration of gerbera. Two levels of day/night temperature were adopted during the vegetative growth stage (VG) and the flowering bud differentiation stage (FBD), namely control (CK; 28/18 °C) and heat stress (HS; 38/28°C) levels. The duration of HS was set as 5, 10, 15, and 20 days, respectively. At the beginning of HS, hourly transpiration was mainly inhibited near noon. With continuation of HS, the duration and extent of inhibition of hourly transpiration increased. Daily transpiration rate was also markedly reduced by HS during the VG (18.9%-31.8%) and FBD (12.1%-20.3%) stages compared to CK. The decrease in the daily transpiration rate was greater for longer duration of heat stress. This reduction of transpiration was the main contributor to stomatal limitation at the beginning of HS, while additional inhibition of root activity, leaf area, and root biomass occurred under long-term HS. The daily transpiration rate could not recover after the end of HS (so-called recovery phase), except when HS lasted 5 days during the VG stage. Interestingly, daily evapotranspiration during HS was substantially increased during the VG (12.6%-24.5%) and FBD (8.4%-17.6%) stages as a result of more increased evaporation (100%-115%) than reduced transpiration. However, during the recovery phase, the daily evapotranspiration was markedly decreased at the VG (11.2%-22.7%) and FBD (11.1%-19.2%) stages. Hence, we suggest that disproportionate variation of transpiration and evaporation during HS, especially at the recovery phase, should be considered in various evapotranspiration models and climate scenarios projections.

Keywords: evaporation; high temperature; leaf stomata; root activity; stomatal conductance; transpiration.